杨木自水解过程中木素对木片颜色影响的研究

Effect of Lignin Content of Poplar Wood Chip on Its Color in Autohydrolysis Pretreatment Process

关键词:  自水解  木素  色度指数  红外光谱

Key Words:autohydrolysis  lignin  chromatic index  infrared spectrum

摘要:研究了杨木在自水解预处理过程中木素含量对木片颜色的影响。结果表明，在不同的自水解处理强度条件下，木片中的木素会发生降解，部分木素结构变化，木片颜色加深。水解木片得率从97.2%降低到83.2%，木片色品指数a*从2.29升高到9.03，色品指数b*变化很小，仅从17.07上升到18.58，明度指数L*从83.26降低到54.96。在本实验自水解强度范围内，自水解液的pH值从5.28降低到3.55。Klason木素和酸溶木素含量之和（总木素）从26.1%降低到19.8%，当自水解强度因子（CHF）达到110.44时，二氧六环木素含量仅为总木素含量的57.5%。

Abstract:The effect of lignin content of poplar wood chip on its color in autohydrolysis pretreatment process was studied. The experimental results showed that with partial lignin degraded and its structure changed in different autohydrolysis severity factors, resulting in darkening of wood chip’s color. When the combined hydrolysis factor （CHF） increased, the yield of autohydrolyzed poplar wood chips decreased from 97.2% to 83.2%. The chip’s chromatic index a* increased from 2.29 to 9.03, index L* reduced from 83.26 to 54.96, and the index b* was changed a little, only increased from 17.07 to 18.58. Within the scope of autohydrolysis severity factors of this study, the pH value of autohydrolysis liquor decreased from 5.28 to 3.55. The total content of Klason lignin and acid soluble lignin reduced from 26.1% to 19.8%. The content of dioxane lignin only accounted for 57.5% of the original lignin content when the CHF was110.44.